1. Field of the Invention
The present invention concerns an imaging tomography apparatus, in particular an x-ray computed tomography apparatus, of the type having at least a first acquisition system (with a first radiator and a first detector for detection of the radiation originating from the first radiator) and a second acquisition system (comprising a second radiator and a second detector for detection of the radiation originating from the second radiator), wherein both acquisition systems are capable of rotating around a common rotation axis.
2. Description of the Prior Art
Tomography apparatuses of the above type are known from U.S. Pat. Nos. 4,991,190; 4,384,359; 4,196,352; 5,966,422 and 6,421,412. An advantage that such tomography apparatuses with multiple acquisition systems exhibit in comparison to a device with one acquisition system is an increased data acquisition rate, which leads to a shorter exposure time, and/or to an increased temporal resolution. A shortened exposure time is of advantage because with it, movement artifacts in the reconstructed image (for example, caused by voluntary and involuntary movements of the patient and/or by arrhythmias in the heart movement) are minimized. This is particularly of importance in the event a larger volume is scanned, for example by means of a spiral scan, such as of the heart. An increased temporal resolution is necessary for representation of, for example, movement cycles, because then the data used for reconstruction of an image must be acquired in the shortest possible time. Conventionally, this has been attempted to be achieved by increasing the rotation speed of the acquisition system, but the acceleration forces, and the mechanical problems resulting therefrom, increase significantly with additional rotation speed. Such problems can be solved aforementioned tomography devices, which have multiple acquisition systems (radiator-detector combinations) arranged separated from one another in the azimuthal direction, meaning “angularly offset” opposite one another. The aforementioned tomography devices are particularly advantageous for the case when such spiral reconstruction algorithms are used for reconstruction of images from the raw data generated by the detectors, which only require projection data from an angular interval of 180°, because then given the presence of, for example, two acquisition systems, the exposure time is reduced to a quarter of the measurement time required for a full rotation.